A conventional battery used as a power source of an electronic device has a problem in which the battery is deteriorated when a temperature during charge or discharge deviates from a given temperature range.
Therefore, it has been conventionally proposed to incorporate a sensor for temperature detection (such as a thermistor) together with a battery, into a battery pack to be attached to an electronic device. Specifically, it is configured that the sensor for temperature detection detects a temperature of a cell of the battery (hereinafter, also simply referred to as battery temperature), during charge to the battery or discharge from the battery to the electronic device. It has been proposed that, when a temperature detected by the sensor deviates from an acceptable temperature range, the charge/discharge is suspended or a charge/discharge current is reduced (see Patent Document 1, for example).
That is, when the battery temperature increases and deviates from the acceptable temperature range during the charge or discharge, the charge to/discharge from the battery is suspended or the charge/discharge current is reduced so as to suppress a temperature increase in the cell of the battery, thereby protecting the battery.